/*
 * Copyright 2006 Jerry Huxtable
 *
 *  Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *  http://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.alee.graphics.filters;

/**
 * A filter which performs a threshold operation on an image.
 *
 * @author Jerry Huxtable
 */
public class ThresholdFilter extends PointFilter
{
    private int lowerThreshold;
    private int upperThreshold;
    private int white = 0xffffff;
    private int black = 0x000000;

    /**
     * Construct a ThresholdFilter.
     */
    public ThresholdFilter ()
    {
        this ( 127 );
    }

    /**
     * Construct a ThresholdFilter.
     *
     * @param t the threshold value
     */
    public ThresholdFilter ( final int t )
    {
        setLowerThreshold ( t );
        setUpperThreshold ( t );
    }

    /**
     * Set the lower threshold value.
     *
     * @param lowerThreshold the threshold value
     * @see #getLowerThreshold
     */
    public void setLowerThreshold ( final int lowerThreshold )
    {
        this.lowerThreshold = lowerThreshold;
    }

    /**
     * Get the lower threshold value.
     *
     * @return the threshold value
     * @see #setLowerThreshold
     */
    public int getLowerThreshold ()
    {
        return lowerThreshold;
    }

    /**
     * Set the upper threshold value.
     *
     * @param upperThreshold the threshold value
     * @see #getUpperThreshold
     */
    public void setUpperThreshold ( final int upperThreshold )
    {
        this.upperThreshold = upperThreshold;
    }

    /**
     * Get the upper threshold value.
     *
     * @return the threshold value
     * @see #setUpperThreshold
     */
    public int getUpperThreshold ()
    {
        return upperThreshold;
    }

    /**
     * Set the color to be used for pixels above the upper threshold.
     *
     * @param white the color
     * @see #getWhite
     */
    public void setWhite ( final int white )
    {
        this.white = white;
    }

    /**
     * Get the color to be used for pixels above the upper threshold.
     *
     * @return the color
     * @see #setWhite
     */
    public int getWhite ()
    {
        return white;
    }

    /**
     * Set the color to be used for pixels below the lower threshold.
     *
     * @param black the color
     * @see #getBlack
     */
    public void setBlack ( final int black )
    {
        this.black = black;
    }

    /**
     * Set the color to be used for pixels below the lower threshold.
     *
     * @return the color
     * @see #setBlack
     */
    public int getBlack ()
    {
        return black;
    }

    @Override
    public int filterRGB ( final int x, final int y, final int rgb )
    {
        final int v = PixelUtils.brightness ( rgb );
        final float f = ImageMath.smoothStep ( lowerThreshold, upperThreshold, v );
        return ( rgb & 0xff000000 ) | ( ImageMath.mixColors ( f, black, white ) & 0xffffff );
    }

    @Override
    public String toString ()
    {
        return "Stylize/Threshold...";
    }
}